Aizawl/Shillong, April 23: The hill states of the Northeast are blessed with a moderate climate — pleasant in summer and enticingly chilled in winter. But this natural air-conditioning will soon become a thing of the past with global warming.

There has been an exponential increase in temperatures in Mizoram over the past 15 years because of rapid deforestation resulting from jhum cultivation, scientists said. Sources from the state’s science and technology department said the mountainous state has become warmer by 2.75 degrees Celsius over the past one-and-a-half years, against the average global surface temperature of 0.6 to 2.5 degrees Celsius.

“The rate at which Aizawl’s temperature is climbing, the scale is even higher than the estimated minimum rate of global warming for the next 50 years,” an official said.

When the mercury soared to over 34 degrees Celsius in Aizawl during the last few days, it became unbearably hot for people like 72-year-old Rozami. “Aizawl was never hot like this when we were young. The increase in temperature appeared to be faster during the past five years,” she said.

The main cause of the rapid increase in temperature in Aizawl, according to science & technology department’s principal scientific officer, Dr Vanlalzara, is the ecological imbalance caused by unplanned urbanisation, rather than the green house effect, which generally is the main cause in the rest of the world.

Local scientist C. Rokhuma, who has been maintaining private meteorological observation since the past 14 years at his Mission Vengthlang residence, has recorded that the average temperature in Mizoram jumped from 25.64 degrees Celsius in 2000 to 30 degrees Celsius in 2011. The average temperature in 2005 was 26.63 degrees Celsius.

“Mizos gave different names to rainfall based on the time of their occurrence. But, what we used to call pawldelh ruah and thuangruah, which came during the spring season, come irregularly and sometimes they don’t come at all. The decreasing rainfall and dewdrops have brought about considerable damage to winter crops and also contributed to increase in temperature,” the 97-year-old said.

According to figures provided by the forest department, covering 10 of the 14 territorial divisions, at least 17,046.33 hectares of forest were destroyed by forest fires caused by jhum.

Meghalaya, too, is grappling with global warming. Tourists from Assam, Bengal and other parts of “mainland” India would flock to Shillong to beat the sweltering heat of the plains.

But April 2014 is different. The heat has been unprecedented. Not too many houses are fitted with fans and air conditioners, compounding the situation.

Since February this year, power supply has been regulated with the Meghalaya Energy Corporation Limited (MeECL) resorting to “load-shedding”. The corporation has declared that there is an “acute shortage of power with rapid depletion of water at the hydroelectric reservoirs of the state”.

There are at least six major hydel power stations in the state, including the Umiam Stage I reservoir, and the water level in these stations has drastically come down due to the heat and wind.

Scanty rainfall in March, while the demand for power has been on the rise, has added to the woes of the residents. The MeECL today announced additional hours of load-shedding for six to seven hours per day.